The quality of a woven or knit fabric can be measured by various properties, such as, the yarn count, thread count, abrasion resistance, cover, weight, yarn bulk, yarn bloom, torque resistance, wrinkle recovery, drape and hand.
Yarn count is the numerical designation given to indicate yarn size and is the relationship of length to weight.
Thread count in woven or knit fabrics, respectively, defines the number ends and picks, and wales and courses per inch of fabric. For example, the count of cloth is indicated by enumerating first the number of warp ends per inch, then the number of filling picks per inch. Thus, 68.times.72 defines a fabric having 68 warp ends and 72 filling picks per inch.
Abrasion resistance is the ability of a fabric to withstand loss of appearance, utility, pile or surface through destructive action of surface wear and rubbing.
Cover is the degree to which underlying structure in a fabric is concealed by surface material. A measure of cover is provided by fabric air permeability, that is, the ease with which air passes through the fabric Permeability measures fundamental fabric qualities and characteristics such as filtration and cover.
Yarn bloom is a measure of the opening and spread of fibers in yarn.
Fabric weight is measured in weight per unit area, for example, the number of ounces per square yard.
Torque of fabric refers to that characteristic which tends to make it turn on itself as a result of twisting It is desirable to remove or diminish torque in fabrics. For example, fabrics used in vertical blinds should have no torque, since such torque will make the fabric twist when hanging in a strip.
Wrinkle recovery is the property of a fabric which enables it to recover from folding deformations.
Hand refers to tactile fabric properties such as softness and drapability.
It is known in the prior art to employ hydroentangling processes in the production of nonwoven materials. In conventional hydroentangling processes, webs of nonwoven fibers are treated with high pressure fluids while supported on apertured patterning screens. Typically, the patterning screen is provided on a drum or continuous planar conveyor which traverses pressurized fluid jets to entangle the web into cohesive ordered fiber groups and configurations corresponding to open areas in the screen. Entanglement is effected by action of the fluid jets which cause fibers in the web to migrate to open areas in the screen, entangle and intertwine.
Prior art hydroentangling processes for producing patterned nonwoven fabrics are represented by U.S. Pat. Nos. 3,485,706 and 3,498,874, respectively, to Evans and Evans et al., and U.S. Pat. Nos. 3,873,255 and 3,917,785 to Kalwaites.
Hydroentangling technology has also been employed by the art to enhance woven and knit fabrics. In such applications warp and pick fibers in fabrics are hydroentangled at crossover points to effect enhancement in fabric cover. However, conventional processes have not proved entirely satisfactory in yielding uniform fabric enhancement. The art has also failed to develop apparatus and process line technology which achieves production line efficiencies.
Australian Patent Specification 287821 to Bunting et al. is representative of the state of the art. Bunting impacts high speed columnar fluid streams on fabrics supported on course porous members. Preferred parameters employed in the Bunting process, described in the Specification Example Nos. XV-XVII, include 20 and 30 mesh support screens, fluid pressure of 1500 psi, and jet orifices having 0.007 inch diameters on 0.050 inch centers. Fabrics are processed employing multiple hydroentangling passes in which the fabric is reoriented on a bias direction with respect to the process direction in order to effect uniform entanglement. Data set forth in the Examples evidences a modest enhancement in fabric cover and stability.
Another approach of art is represented by European Patent Application No. 0 177 277 to Willbanks et al. which is directed to hydropatterning technology. Willbanks impinges high velocity fluids onto woven, knitted and bonded fabrics for decorative effects. Patterning is effected by redistributing yarn tension within the fabric - yarns are selectively compacted, loosened and opened - to impart relief structure to the fabric.
Fabric enhancement of limited extent is obtained in Willbanks as a secondary product of the patterning process. However, Gilpatrick fails to suggest or teach a hydroentangling process that can be employed to uniformly enhance fabric characteristics. See Willbanks Example 4, page 40.
There is a need in the art for an improved woven textile hydroenhancing process which is commercially viable. It will be appreciated that fabric enhancement offers aesthetic and functional advantages which have application in a wide diversity of fabrics. Hydroenhancement improves fabric cover through dynamic fluid entanglement and bulking of fabric yarns for improved fabric stability. These results are advantageously obtained without requirement of conventional fabric finishing processes.
The art also requires apparatus of uncomplex design for hydroenhancing textile materials. Commercial production requires apparatus for continuous fabric hydroenhancing and in-line drying of such fabrics under controlled conditions to yield fabrics of uniform specifications.
Accordingly, it is a broad object of the invention to provide an improved textile hydroenhancing process and related apparatus for production of a variety of novel woven and knit fabrics having improved characteristics which advance the art.
A more specific object of the invention is to provide a hydroenhancing process for enhancement of fabrics made of spun and spun/filament yarn.
Another object of the invention is to provide a hydroenhancing process having application for the fabrication of novel composite and layered fabrics.
A further object of the invention is to provide a hydroenhancing production line apparatus which is less complex and improved over the prior art.